[Transcatheter occlusion of the persisting arterial duct]. / Der Verschluss des persistierenden Ductus arteriosus Botalli mittels Herzkathetertechnik.

BACKGROUND: Transcatheter occlusion of the persisting arterial duct (PDA) is feasible using different techniques like coil-embolization (CE), Rashkind PDA occluder (Rash), Amplatzer Duct Occluder (ADO). Comparative studies with this devices in relation to the size of the PDA and the device are missing. Aim of this study was to evaluate the different systems at the own patient population. PATIENTS AND METHODS: From 1993 to 12/2001 transcatheter occlusion was attempted in 92 patients aged 4,13 years (range 0,07 to 14,39 years) using CE, Rash or ADO. All patients received echocardiographic examinations 24 hours before and after intervention, after 3, 6, and 12 months and than yearly. RESULTS: 91/92 PDAs could be successfully closed by 97 interventions. There were 63 CE, 25 Rash and 9 ADO performed. Primary closure rate was 75 % for Rash, 80 % for ADO and 80,8 % for CE (n. s.) and after 6 months 88 % for Rash, 92,3 % for CE and 100 % for ADO (p < 0,001), although the size of the PDA increased significantly from CE (2,14 + 1,1 min) to Rash (3,2 +/- 1,3 min) to ADO (4,9 +/- 1,9 min) (p < 0.05). In 6/7 pts with residual shunts complete occlusion could be achieved by second intervention. CONCLUSION: In dependency of the size of the PDA and the right choice of the occluder almost all PDAs are closable with transcatheter techniques.

Normal values of M mode echocardiographic measurements of more than 2000 healthy infants and children in central Europe.

OBJECTIVE: To obtain normal M mode (one dimensional) echocardiographic values in a substantial sample of normal infants and children. DESIGN: Data were obtained over three years from a single centre in central Europe. PATIENTS: 2036 healthy infants and children aged one day to 18 years. METHODS: In line with recommendations for standardising measurements from M mode echocardiograms, and using digital echocardiographic equipment, measurements were obtained of the following: right ventricular anterior wall thickness at end diastole, right ventricular end diastolic dimension, thickness of interventricular septum at end diastole and end systole, thickness of posterior wall of the left ventricle at end diastole and end systole, left ventricular dimension at end diastole and end systole, pulmonary and aortic valve diameter, and left atrial dimension. RESULTS: Measurements are presented graphically on centile charts with respect to body surface area, and as tables with mean and 2 SD values for newborns in relation to body weight, and for infants and children in relation to body surface area. Best fitting regression equations are given for each measured variable, using the 50th centile values. CONCLUSION: In comparison with previously published normal values, the presented charts and tables make it possible to judge echocardiographic measurements of a particular patient as normal or abnormal.

Reduced inotropic support after aprotinin therapy during pediatric cardiac operations.

BACKGROUND: Several reports indicate that aprotinin treatment before and during cardiopulmonary bypass (CPB) might have a protective effect on the myocardium. We evaluated the hemodynamic effects of perioperative aprotinin treatment. METHODS: We conducted a randomized, double-blind, placebo-controlled trial in 34 infants (mean age, 2.5 years) who had cardiac operations. Half of the patients received high-dose aprotinin therapy. There were no significant differences between the aprotinin and placebo groups with respect to age, weight, sex, aortic cross-clamp time, and CPB time. The following data were recorded at arrival in the intensive care unit 6, 12, 24, and 48 hours after termination of CPB: heart rate, blood pressure, left atrial pressure, central-peripheral temperature difference, arterial-central venous oxygen saturation difference, urine output, serum creatinine, lactate and neutrophil elastase levels, the Doppler echocardiographic factors shortening fraction and preejection period/left-ventricular ejection time, and cumulative doses of catecholamines (epinephrine), enoximone, and furosemide. RESULTS: No hemodynamic variable showed any significant difference between aprotinin and placebo groups. Urine output, creatinine, lactate, and elastase levels, as well as the cumulative doses of furosemide and epinephrine were not significantly different. Twelve hours after CPB 10 patients in the placebo group and 4 in the aprotinin group had received enoximone (p<0.05). The placebo group had received significantly larger doses of enoximone than the aprotinin group at arrival in the intensive care unit (0.13+/-0.05 versus 0 mg/kg), 12 hours after CPB (0.58+/-0.14 versus 0.18+/-0.09 mg/kg), 24 hours after CPB (1.11+/-0.24 versus 0.42+/-0.16 mg/kg), and 48 hours after CPB (1.61+/-0.40 versus 0.86+/-0.28). At 6 hours the difference did not reach statistical significance. CONCLUSIONS: Clinical and hemodynamic status of the aprotinin-treated patients was similar to that of the placebo-treated patients in the first 48 hours after CPB. The placebo group, however, required significantly more inotropic support by enoximone than the aprotinin group to achieve this goal.

Evaluation of gastric intramucosal pH during and after pediatric cardiac surgery.

OBJECTIVES: In adult patients, intramucosal pH (pHi) has been advocated to detect postoperative complications. The purpose of our study was to evaluate this technique in pediatric patients during and after cardiac surgery. METHODS: Thirty-five infants (age: 5 days to 15 years, median 1.8 years; and weight: 3.2-32 kg, median 9.8 kg) were studied. pHi was measured before cardiopulmonary bypass (CPB), after 30 min of CPB, prior to weaning off CPB, at intensive care unit arrival, and 6, 12, 24, 48 and 72 h after surgery. RESULTS: There were no complications related to the tonometer. A pathologically low pHi < 7.32 was found during surgery in less than 17%, at intensive care unit arrival in 83% and after 48 h in 18%. pHi values were lower (P < 0.05) at intensive care unit arrival (7.25 +/- 0.08) and after 6 h (7.28 +/- 0.09) than afterwards. pHi correlated with arterial pH (r = 0.66), central-peripheral temperature difference (r = -0.36), lactate (r = -0.32) and central venous pressure (r = -0.21). Patients after a Fontan procedure had postoperatively a lower pHi than after other operations (P < 0.05). None of the patients died or developed organ failure. Six patients had signs of organ dysfunction. Their pHi (median 7.23, range 7.14-7.28) could not differentiate them from the other patients. CONCLUSIONS: With current equipment, tonometry cannot be recommended for the management of pediatric patients after cardiac surgery. However, as a semi-invasive method tonometry deserves further evaluation.

Microdeletion 22q11 in complex cardiovascular malformations.

Besides DiGeorge, velocardiofacial and conotruncal anomaly face syndromes, some of the isolated congenital heart diseases have also been associated with a chromosomal deletion in 22q11. These disease entities, which had originally been considered to have a different genetic background, are now included in the CATCH-22 microdeletion complex. CATCH 22 is an acronym for cardiac defect, abnormal facies, thymic hypoplasia or aplasia and T-cell deficiency, cleft palate, hypoparathyroidism, and hypocalcemia. In the present study, we focused on the complex cardiovascular defects (CCVD) and screened 40 patients for a microdeletion of 22q11 by fluorescence in situ hybridization using the D22S75 DNA probe and for associated CATCH features. The patients were from genetic counseling (n = 15) or fetopathology (n = 3) of the Clinical Genetics Department in Marburg and from the Pediatric Cardiology Department (n = 22) in Mainz. Monosomy 22q11 was detected in 9 cases (= 22.5%). Familial transmission with one mildly affected parent and one affected sib each was proven in two cases. The CCVDs comprised complex conotruncal defects such as tetralogy of Fallot, double outlet right ventricle, transposition of great arteries and truncus arteriosus communis, or anomalies of the derivatives of the branchial arch arteries in association with a ventricular septal defect, including one case of atresia of the ductus arteriosus with pulmonary artery aneurysm and resulting in fetal hydrops. All 13 patients with a deletion of 22q11 showed at least one additional CATCH symptom. Most consistently, facial dysmorphy was apparent (92%), while hypocalcemia, mostly at threshold values, was present in 62% and thymic hypoplasia including borderline low T-lymphocyte numbers was observed in 41%. None of the patients presented with a cleft palate. A high intrafamilial variability in expression was also evident with respect to the CCVD. Our findings indicate that seemingly isolated complex cardiovascular defects associated with a 22q11 microdeletion most probably do not represent a distinct subgroup within the CATCH-22 complex but are syndromal in nature with extracardiac features that are often overlooked.

[Surgical closure of atrial septum defects via right-sided thoracotomy. Value with reference to the development of interventricular closure techniques]. / Operativer Verschluss von Vorhofseptumdefekten über eine rechtsseitige Thorakotomie. Stellenwert unter Berücksichtigung der Entwicklung interventioneller Verschlusstechniken.

Surgical closure of atrial septal defect is a safe and effective procedure with low morbidity and mortality. A right anterior thoracotomy approach is a suitable alternative to that through a median sternotomy and provides superior cosmetic results. Thirty patients at the age of 1 year, 3 months to 49 years underwent repair of atrial septal defects through a right thoracotomy. Twenty-four patients had secundum, three ostium primum, two sinus venosus defect, and one patient had Scimitar's syndrome. Details of the surgical procedure on cardiopulmonary bypass are presented. There was no operative or late mortality, and no morbidity directly related to the alternative approach. All patients or their parents considered the cosmetic result fair or satisfying. The following paper reflects our experience with the thoracotomy approach for repair of atrial septal defects, as well as a critical review of new developments in interventional ASD occlusion techniques.

Continuous measurement of cardiac output by the Fick principle in infants and children: comparison with the thermodilution method.

OBJECTIVE: To compare a system that continuously monitors cardiac output by the Fick principle with measurements by the thermodilution technique in pediatric patients. DESIGN: Prospective direct comparison of the above two techniques. SETTING: Pediatric intensive care unit of a university hospital. PATIENTS: 25 infants and children, aged 1 week to 17 years (median 10 months), who had undergone open heart surgery were studied. Only patients without an endotracheal tube leak and without a residual shunt were included. METHODS: The system based on the Fick principle uses measurements of oxygen consumption taken by a metabolic monitor and of arterial and mixed venous oxygen saturation taken by pulse- and fiberoptic oximetry to calculate cardiac output every 20s. INTERVENTIONS: In every patient one pair of measurements was taken. Continuous Fick and thermodilution cardiac output measurements were performed simultaneously, with the examiners remaining ignorant of the results of the other method. RESULTS: Cardiac output measurements ranged from 0.21 to 4.55 l/min. A good correlation coefficient was found: r2 = 0.98; P < 0.001; SEE = 0.41 l/min. The bias is absolute values and in percent of average cardiac output was - 0.05 l/min or - 4.4% with a precision of 0.32 l/min or 21.3% at 2 SD, respectively. The difference was most marked in a neonate with low cardiac output. CONCLUSION: Continuous measurement of cardiac output by the Fick principle offers a convenient method for the hemodynamic monitoring of unstable infants and children.

[Analgosedation with fentanyl/midazolam after correction of congenital heart defects]. / Analgosedierung mit Fentanyl/Midazolam nach Korrektur angeborener Herzfehler.

There is no standard therapy in the management of postoperative pain control following corrective cardiac surgery of congenital heart disease. Assessment in the preverbal age is difficult. In a randomized study we compared a combined treatment of fentanyl and midazolam, given as continuous infusion versus single dose application. A pain assessment score was used to measure the effectiveness of analgosedation in addition to recording nurseries observations. Fentanyl and midazolam are an appropriate combination for postoperative pain treatment. Continuous application is considered to be more effective concerning basic anxiety, cumulative dosage and to avoid volume overload in infants and young children, following cardiac surgery; overdosage was not observed.

Evaluation of the pulse wave arrival time as a marker for blood pressure changes in critically ill infants and children.

OBJECTIVE: Pulse arrival time (PAT), which is the interval between the R wave of the electrocardiogram (ECG) and the arrival of the pulse wave peripherally, has been reported to be suitable for use as an indirect measure of blood pressure change. The purpose of this study was to evaluate, in critically ill infants and children, the degree to which 1/PAT covaries with systolic, diastolic, and mean blood pressure, as well as heart rate. METHODS: A laboratory device was used to calculate PAT in real time from the ECG and the plethysmographic curve of pulse oximetry used for routine monitoring. Calculated PAT and corresponding blood pressures and heart rate were stored on hard disk. A total of 15 critically ill patients, aged 6 days to 16 years, weighing 3 to 80 kg, were studied. RESULTS: In all patients, one period of 11,000 to 36,000 beats could be evaluated. Mean correlation coefficients were best for systolic blood pressure (r = 0.73), followed by mean blood pressure (r = 0.68) and diastolic blood pressure (r = 0.61), and, finally, heart rate (r = 0.52). In 7 patients, the correlation coefficient for systolic blood pressure was > 0.9; but, in 4 patients, it was < 0.5. CONCLUSIONS: We conclude that the correlation between 1/PAT and systolic blood pressure is not strong enough to serve as a marker for blood pressure changes in critically ill infants and children. This may be due to changes of the preejection period, which is part of the PAT.

Norepinephrine, enoximone, and nitric oxide for treatment of myocardial stunning and pulmonary hypertension in a newborn with diaphragmatic hernia.

A newborn with right diaphragmatic hernia suffered myocardial stunning and suprasystemic pulmonary hypertension secondary to postpartal asphyxia. In addition to conventional therapy, norepinephrine, enoximone, and inhalational nitric oxide were successfully used. Norepinephrine improved myocardial perfusion pressure; the addition of enoximone, a phosphodiesterase-inhibitor, to beta-adrenergic agents increased cardiac performance. with decreasing concentrations of inhalational nitric oxide, severe pulmonary hypertension resolved after a few days, suggesting that transient endothelial dysfunction was partially responsible for pulmonary vasoconstriction in the newborn with congenital diaphragmatic hernia.

Mitral and aortic regurgitation in 84 patients with mucopolysaccharidoses.

UNLABELLED: In echocardiographic and necropsy studies nodular thickening of the mitral valve and, less frequently, of the aortic valve has been found in 60%-90% of patients with mucopolysaccharidoses (MPS). Little is known about the haemodynamic consequences of these morphological changes. In this study 84 unselected patients with different enzymatically proven MPS and 84 age and sex matched, healthy persons were studied prospectively by colour Doppler flow mapping. The patients' age ranged from 1 to 47 years (median 8.1 years). Mitral and aortic regurgitation were defined as a holosystolic or holodiastolic jet originating from the valve into the left atrium or the left ventricular outflow tract, respectively, with peak velocities exceeding 2.5 m/s. Of the 84 patients with satisfactory studies, mitral regurgitation was detected in 64.3% and aortic regurgitation in 40.5%, respectively. Regurgitation was severe in 4.8% of mitral valves and 8.3% of aortic valves. The frequency of aortic and/or mitral regurgitation was 75% in all patients, 89% in MPS I, 94% in MPS II, 66% in MPS III, 33% in MPS IV, and 100% in MPS VI. Combined mitral and aortic regurgitation was present in 29% of our patients. None of the control persons showed mitral or aortic regurgitation. CONCLUSION: Aortic and mitral regurgitation are more frequent in patients with MPS than previously thought and that therefore these patients should have regular colour Doppler flow mapping and antibiotic prophylaxis when required.

Independent right lung high frequency and left lung conventional ventilation in the management of severe air leak during ARDS.

Pulmonary air leaks are one of the most common problems in patients with the adult respiratory distress syndrome, ARDS. We report what we believe to be the first case in which unilateral high-frequency ventilation combined with contralateral conventional positive pressure ventilation has been used successfully to manage severe air leak in an infant with ARDS.

[Treatment of acute low cardiac output syndrome after surgery of congenital heart defects: value of enoximone]. / Behandlung des akuten Low-cardiac-output-Syndroms nach Operationen angeborener Herzfehler: Stellenwert von Enoximon.

Children undergoing cardiac surgery are at additional risk for postoperative low cardiac output syndrome (LCOS). Anticipation of the syndrome from preoperative hemodynamic condition, surgical procedure, and adverse intraoperative events is a key to successful postoperative management. Inotropic support is primarily based on catecholamines. However, uncoupling of human cardiac beta-adrenoceptors during cardiopulmonary bypass with cardioplegic cardiac arrest may be the reason why many patients respond only weakly to beta-adrenoceptor agonists. Phosphodiesterase (PDE) inhibitors act by reducing intracellular breakdown of cAMP, which is elevated independently from beta-receptors. The use of PDE-inhibitors might be advantageous in patients with uncoupled beta-adrenoceptors, as occurs after cardiopulmonary bypass. In addition, PDE-inhibitors can prevent further downregulation of the adrenoceptors due to avoiding prolonged therapy by beta-agonists. In this context, the addition of enoximone, a PDE-inhibitor, to adrenergic agents has been found useful in increasing cardiac output in children with catecholamine-resistant LCO, as well as in children with compensated hemodynamics during catecholamine therapy.

Nitric oxide and prostacyclin lower suprasystemic pulmonary hypertension after cardiopulmonary bypass.

In a 3-week-old male newborn persistent suprasystemic pulmonary hypertension developed after surgical valvulotomy for a critical aortic valve stenosis. Because of a residual transvalvular pressure gradient of 35 mmHg and postoperative left as well as right ventricular dysfunction, treatment with inhaled nitric oxide (NO) and intravenously infused prostacyclin (PGI2) was attempted. Low-dose inhaled NO and low dose PGI2 corrected severe pulmonary hypertension and led to an increase in cardiac output. Treatment with NO but not PGI2 was accompanied by a rise in PaO2 and systemic blood pressure. Interruption of NO administration led to a rapid increase in pulmonary arterial pressure to suprasystemic levels. With continued i.v. PGI2 and decreasing concentrations of NO, severe pulmonary hypertension resolved after a few days suggesting that a transient endothelial dysfunction was partially responsible for pulmonary vasoconstriction. NO inhalation appears to be an effective new tool in the treatment of severe pulmonary hypertension following cardiac surgery.

Effects of tolazoline and prostacyclin on pulmonary hypertension in infants after cardiac surgery.

OBJECTIVE: To evaluate the hemodynamic effects of tolazoline and prostacyclin in infants with pulmonary vasospasm after cardiac surgery. DESIGN: Prospective cohort study. SETTING: Pediatric ICU. PATIENTS: The cohort consisted of 42 infants and children with congenital heart disease and pulmonary hypertension who underwent corrective surgery and were monitored postoperatively using pulmonary artery catheters. Fourteen infants (2 to 12 months old) in this group required postoperative treatment with tolazoline or prostacyclin. INTERVENTIONS: Tolazoline was administered as a bolus of 0.5 mg/kg for treatment of persistent pulmonary hypertension or acute pulmonary hypertensive crisis. If its effectiveness was proved after 30 mins by hemodynamic measurements, a continuous iv infusion of 0.5 mg/kg/hr was established. Higher doses of tolazoline were avoided. If tolazoline treatment did not fulfill the criteria for pulmonary vasodilation, prostacyclin was given by continuous iv infusion at a starting rate of 5 ng/kg/min, followed by 10 ng/kg/min. In three patients, the infusion rate was increased to 15 ng/kg/min. RESULTS: Bolus administration of tolazoline resulted in a distinct pulmonary vasodilation in seven infants: mean pulmonary artery pressure and pulmonary vascular resistance decreased by an average of 35% and 45%, respectively. In these patients, tolazoline was infused over the following 12 to 72 hrs. One infant who received tolazoline for 72 hrs developed a clinically important gastrointestinal hemorrhage. In seven nonresponders to tolazoline, prostacyclin (PGI2) at an infusion rate of 5 ng/kg/min led to pulmonary vasodilation in five patients, at an iv infusion rate of 10 ng/kg/min in all seven infants studied. The latter dose of PGI2 reduced the mean pulmonary artery pressure by an average of 37%, and pulmonary vascular resistance by 43%. Transient withdrawal of prostacyclin in five infants demonstrated its short half-life and clinical effectiveness. Apart from a facial flush, no side-effects were encountered using PGI2 as an infusion over durations ranging from 12 to 504 hrs. CONCLUSIONS: These data suggest that, if tolazoline in a relatively low dose proves to be inefficient, prostacyclin can still be used as a safe and effective drug for treatment of pulmonary vasospasm. Prostacyclin offers more than a pharmacologic alternative to increased tolazoline dosages.

Determination of cardiac output by an angle and diameter independent dual beam Doppler technique in critically ill infants.

OBJECTIVE: To compare cardiac output measurements in critically ill infants by the dual beam Doppler and thermodilution techniques. DESIGN: Prospective direct comparison of the two techniques. For statistical evaluation one randomly assigned paired measurement of every patient was used. SETTING: Paediatric intensive care unit in a university hospital. PATIENTS: 18 infants after open heart surgery aged 4-25 months (weight 4-10 kg). INTERVENTIONS: Cardiac output measurements by dual beam Doppler and thermodilution techniques were performed within 10 minutes of each other and without knowledge of the results of the other methods. Multiple measurements were performed on some patients with a pharmacological or electrophysiological intervention or with a minimum of six hours between each pair of measurements. MEASUREMENTS AND MAIN RESULTS: Three patients were excluded because of an inadequate Doppler signal or a significant residual shunt. Cardiac output measurements ranged from 0.4 to 2.2 l/min for the thermodilution technique and from 0.5 to 2.1 l/min for the dual beam Doppler technique. Agreement between both methods was acceptable. The mean difference between the two methods was 0.026 l/min with two standard deviations ranging from -0.20 to 0.26 l/min. CONCLUSION: The dual beam Doppler technique was shown to have promise for the non-invasive determination of cardiac output in critically ill infants.

Evaluation of the valve area underestimation by the continuity equation.

During the last years, noninvasive determination of the aortic valve area by Doppler echocardiography using the continuity equation became popular. However, a systematic valve area underestimation of about 15% compared to invasive measurements using the Gorlin formula has been reported. The cause therefore is unknown. The purpose of this study was to evaluate whether the valve area underestimation by the Doppler method might be due to differences in the hydrodynamic background of both methods. This comparison is facilitated by the fact that the Gorlin formula is based on the continuity equation. Compared to the continuity equation, there are four changes within the Gorlin formula: (1) the additional use of a discharge coefficient, which leads to valve area overestimation by the factor 1.17; (2) neglect of the pre-stenotic velocity, causing further overestimation by the factor 1.036 (in mild stenosis this factor may be 1.18 and more); (3) the wrong calculation of the mean pressure drop, which leads to a mean change by the factor 0.95, and (4) the incorrect substitution of the height by the pressure drop in the derivation of the Gorlin formula causes underestimation by the factor 0.97. Combining these four factors results in valve area overestimation of the Gorlin formula compared to the continuity equation by the factor 1.12. This explains to a large extent the valve area underestimation by the continuity equation.